The broad, long-term goal of this proposal is to establish a comprehensive program for the prevention of obesity among schoolchildren of the White Mountain Apache Tribe in Whiteriver, Arizona. The specific aims for this three-year project (Phase I) are: a) to assess the prevalence and characteristics of obesity among children attending all six elementary schools in the Apache reservation (grades k-5); b) to identify the major dietary, cultural and behavioral factors associated with excess body weight among elementary school children; c) to evaluate the feasibility of interventions aimed at modifying dietary energy intake and physical activity of schoolchildren; d) to develop and test the instruments and to train the personnel needed to support a school-based long-term intervention for the prevention of obesity; and e) to collaborate with other field sites in the development of a muticenter, randomized intervention trial for the prevention of obesity in American Indian school children. Using social sciences research techniques, our proposal will identify the major behavioral and psychosocial risk factors associated with obesity in elementary school children. We will then develop school-based interventions focused on behavioral change and participatory learning. These interventions will be complemented with family-based programs to ensure consistent parental involvement, and to engage childrens as agents of change. An important consideration will be to develop interventions with strongest potential for long-term self-sustainability. To achieve these goals, we have assembled a multidisciplinary team of experts in pediatric obesity, social sciences, nutrition education, American Indian health, epidemiology and biostatistics. Building on 15 years of continuing collaboration between the Whiteriver Apache community and the Johns Hopkins School of Public Health, our proposal has received strong support from the White Mountain Apache Tribe, the Whiteriver Unified School District, and the Whiteriver Indian Health Service Unit.